C# Array index out of bounds error

Full disclosure: This is for a homework assignment. This is driving me nuts. I'm writing a Discrete Cosine Transform function and have it basically complete, but I'm running into an IndexOutOfRange exception. Code is below: ``` static int[][] DiscreteCosineTransform(int[][] pIn) { int[][] cosP = pIn; double SumCosP = 0; double Cx = 0; double Cy = 0; Console.WriteLine("Discrete Cosine Transformed Array:"); for(int i = 0; i < 8; i++) { if (i == 0) Cx = 1 / Math.Sqrt(2); else Cx = 1; for(int j = 0; j < 8; i++) { if (j == 0) Cy = 1 / Math.Sqrt(2); else Cy = 1; for (int x = 0; x < 8; x++) { for (int y = 0; y < 8; y++) { SumCosP += cosP[x][y] * Math.Cos(((2 * x + 1) * i * Math.PI) / 16) * Math.Cos(((2 * y + 1) * j * Math.PI) / 16); } } pIn[i][j] = (int)(0.25 * Cx * Cy * SumCosP); Console.Write(" " + pIn[i][j] + " "); } Console.WriteLine(); } Console.WriteLine(); return pIn; } ``` Where pIn is: ``` int[][] P = new int[][] { new int[]{10,10,10,10,10,10,10,10}, new int[]{10,20,20,20,20,20,20,10}, new int[]{10,20,30,30,30,30,20,10}, new int[]{10,20,30,40,40,30,20,10}, new int[]{10,20,30,40,40,30,20,10}, new int[]{10,20,30,30,30,30,20,10}, new int[]{10,20,20,20,20,20,20,10}, new int[]{10,10,10,10,10,10,10,10} }; ```